1. Technical Field
The present invention relates to a coloring composition in which color and ozone gas fastness are, excellent, bronze gloss is suppressed, print quality such as print density is high, temporal stability and preserve performance are high at a high concentration, and particularly, discharge stability after long-term storage in an aqueous solution is excellent, an ink for inkjet recording using the coloring composition, a method for inkjet recording using the ink for inkjet recording, an ink cartridge, and an inkjet recording material.
2. Background Art
Recently, as computers are distributed, inkjet printers are widely used to print on paper, film, fabric, and the like in households as well as in offices.
The inkjet recording method includes a method of discharging a liquid drop by applying pressure by a piezo element, a method of discharging a liquid drop by generating bubbles in ink by heat, a method of using an ultrasonic wave, and a method of absorbing a liquid drop by electrostatic force and discharges it. An aqueous ink, an oily ink or a solid (melt type) ink is used as an ink for inkjet recording. Among these inks, an aqueous ink is mostly used in terms of manufacture, handlability, odor, stability, etc.
A colorant used as ink for inkjet recording needs to ensure favorable solubility to a solvent, recording at a high concentration, favorable colors, excellent fastness to light, heat, air, active gas (NOx, Sx, other than oxidative gas such as ozone) in an environment, and water or chemicals, good settlement to an image-receiving material, low spreading, excellent preservation as ink, non-toxicity, high purity, and availableness at low price.
In addition, since an aqueous ink is easily decomposed and fungi is easy to grow, if the ink is left for a long time, the physical property of the ink caused by the decomposition may be changed or the grown fungi may become an alien substance of the ink, so that the ink discharge is significantly deteriorated. Furthermore, since the color of the colorant having the fungi easily affects color tone, the color of the ink after storage or the color storability of images over time after printing may deteriorate.
Regarding the ink for inkjet recording containing preservatives, for example, Japanese Patent Publication No. 4538229 discloses an ink for inkjet recording which is made by dissolving or dispersing an azo dye or a phthalocyanine dye having a particular structure, wherein the dye is an aqueous dye having a noble oxidation potential than 1.0 V (vsSCE) and the ink contains at least one preservative. Also, Japanese Patent Application Laid-Open No. 2007-217533 discloses an ink for inkjet recording containing a phthalocyanine dye having a particular structure, and a thiazole compound.
However, it is very difficult to seek a dye that satisfies these requirements at a high level.
Although various dyes or pigments have been suggested for inkjet and have been used in practice, a colorant that satisfies all requirements has not yet been found. A conventionally well-known dye or pigment having an assigned color index number (C.I.) is difficult to balance fastness and the color required in the ink for inkjet recording.
The present invention has been made in view of such circumstances, and an object thereof is to provide a coloring composition in which color and ozone gas fastness are excellent, bronze gloss is suppressed, print quality such as print density is high, temporal stability and preserve performance are high at a high concentration, and particularly, discharge stability after long-term storage in an aqueous solution is excellent, an ink for inkjet recording using the coloring composition, a method for inkjet recording using the ink for inkjet recording, an ink cartridge, and an inkjet recording material.
To solve the aforesaid problems, the present inventors have intensively studied and found that the object of the invention may be achieved by a coloring composition described below. The functioning mechanism thereof is unclear, but can be inferred as follows.
First, the coloring composition of the present invention contains a dye represented by Formula (2) and having strong associativity and high fastness to ozone gases and the like, and a dye represented by Formula (1) and having weak associativity and high print density. Accordingly, it is considered that associativity of dyes may be controlled and high fastness to ozone gases and high print density may be balanced.
It is also considered that the control of association allows for favorable color and suppressed bronze gloss.
Further, it is considered that in the coloring composition of the present invention, the preservative property of the coloring composition is improved by containing preservative performance and the emergence of fungi is prevented by the antifungal action of the preservatives, and as a result, clogging in a nozzle, etc. rarely occurs and high-quality printing materials may be obtained.
Furthermore, the use in combination with a compound represented by Formula (1), a compound represented by Formula (2), and preservatives is considered to inhibit the emergence or precipitation of fungi, which is noticeable in an aqueous solution of high concentration containing no organic solvent during long-term storage. As a result, it is considered that the temporal stability of the coloring composition is improved, good discharge stability is obtained despite the use of the ink made in an aqueous solution at high concentration after long-term storage, and high quality printing is possible.